Aryl phosphonites, a process for their production and their use for stabilizing plastics

ABSTRACT

A process for the preparation of aryl phosphonites of the formula V ##STR1## wherein the radicals and n are defined in the disclosure. The invention further relates to a plastic molding composition, in particular a polyolefin molding composition containing aryl phosphonites of the formula V.

DESCRIPTION

The present invention relates to new diaryl phosphonites and tetraaryldiphosphonites, a process for their preparation and their use forstabilizing plastics, in particular polyolefins.

It is known that synthetic polymers have to be protected againstunwanted oxidative, thermal and photochemical damage during thepreparation, the processing and the use by means of stabilizers orstabilizer systems. Such stabilizers comprise, for example, a phenolicantioxidant which should ensure in particular the long-term usestability of the molded article, and one or more costabilizers, whichcontrol the processing stability and in some cases also reinforce thesynergistic effect of the phenolic component.

Conventional stabilizers include ortho-alkylated aryl phosphites andphosphonites, the latter being distinguished in particular by extensivestability to hydrolysis.

It is known from European Patent 5,447 (=U.S. Pat. Nos. 4,406,842 and4,474,914=Japanese Laid-Open Application 79-141,753) thatortho-alkylated phenyl phosphonites of the formula ##STR2## can beprepared by reaction of alkyl- or arylphosphonous dichlorides withortho-alkylated phenols in the presence of at least stoichiometricamounts of a suitable base for neutralizing the hydrochloric acidformed. Although the general definitions given in this patent arespecified to the extent that within preferred, relatively narrowdefinitions for the radicals R₁, R₂ and R₃, the radical R₁ can bephenyl, o-, m-, p-tolyl, o-, m-, p-xylyl, mesityl, o-cumyl,p-tert-butylphenyl, 2,4-di-tert-butylphenyl, 2,4,6-tri-tert-butylphenyl,or 2,4-di-tert-octylphenyl, R₂ can be tert-butyl, tert-amyl, tert-octyl,tert-octadecyl and R₃ can be H, methyl, i-propyl, tert-butyl, tert-amyl,n-hexyl, tert-octyl, tert-dodecyl or n-octadecyl, α-methylbenzyl orα,α-dimethylbenzyl; of the possible combinations among these, however,only two embodiment examples where R₁ is phenyl and R₂ and R₃ aresimultaneously tert-butyl or tert-octyl are mentioned, and furthermore 6table examples, in three of which R₁ is also phenyl and either R₂ istert-octyl and R₃ is methyl or R₂ is tert-butyl and R₃ is hydrogen or R₂and R₃ simultaneously are α,α-dimethylbenzyl. Accordingly, these 5compounds cannot be deemed new.

However, the process of European Patent 5,447 can be carried out only toa limited extent because of the difficult synthesis of thedichlorophosphanes required as precursors, which is of course adisadvantage if an industrial preparation is taken into consideration.Thus, for example, of the aromatic derivatives, onlyphenyldichlorophosphane is an industrially available product, whichmakes derivatives of benzenephosphonous acid only available, which makesit easy to understand why, of the compounds in which R₁ is an arylradical, precisely only those having unsubstituted phenyl are cited.

However, in order to meet the high demands made in practice on thestability, efficiency, nonvolatility and migration behavior ofstabilizers for polymers, it is desirable that especially the morehighly substituted derivatives of arylphosphonous acids be available.However, they are not accessible by known processes, due to the factthat until now the preparation of the precursors has not beeneconomically feasible.

As a result, new stabilizers having improved properties and processesfor their preparation, which do not have these disadvantages are verydesirable.

Accordingly, the present invention relates to aryl phosphonites of theformula V (see formula sheet), i.e. diaryl phosphonites where n=1 andtetraaryl diphosphonites where n=2, in which A is non-existent--i.e. thetwo rings carry hydrogen--or a divalent hydrocarbon bridge having 1 to 6carbon atoms which may be substituted by groups mentioned further belowunder R¹, or is a hetero atom such as oxygen or sulfur, cycloalkylidenehaving 4 to 8 carbon atoms or phenylalkylidene having 7 to 12 carbonatoms, R¹ as monovalent radical is a phenyl or benzyl radical, each ofwhich carry 1 to 3 substituents, or is a-methylbenzyl,α,α-dimethylbenzyl, naphthyl or a naphthyl radical carrying 1 to 5substituents, in which the substituents are identical or different andare a non-aromatic hydrocarbon radical, an alkoxy radical, an alkylthioradical or a dialkylamino radical, in which the alkyl radicals each have1 to 8 carbon atoms, aryl or aryloxy each having 6 to 10 carbon atoms orhalogen having an atomic number from 9 to 35, and as divalent radical anaphthylene radical which is unsubstituted or carries 1 to 4non-aromatic hydrocarbon radicals each having 1 to 8 carbon atoms assubstituents, or, if A is non-existent, a phenylene radical which isunsubstituted or is substituted by up to 2 non-aromatic hydrocarbonradicals each having 1 to 8 carbon atoms,

R² is a non-aromatic hydrocarbon radical having 1 to 18 carbon atoms,aryl, arylmethyl, arylethyl or arylisopropyl, in which the aryl in eachcase contains 6 to 10 carbon atoms, and

R³ is hydrogen or a group mentioned under R²,

where, in the compounds in which n=1 and R¹ is phenyl, those areexcepted in which simultaneously

R² and R³ are each tert-butyl,

R² is tert-butyl and R³ is hydrogen,

R² is tert-octyl and R³ is methyl,

R² and R³ are each tert-octyl and

R² and R³ are each α,α-dimethylbenzyl.

The specific class of compounds according to the invention in which A isnon-existent has the formula I (see formula sheet) for the preparationof which diaryl halophosphonites II (see formula sheet) are used. In allcases, compounds in which R¹ is unsubstituted or substituted naphthylare particularly preferred.

In the compounds of the formula I according to the invention, R¹ asmonovalent radical is, for example, a phenyl or benzyl radical carrying1 to 3 substituents, such as the C₁ -C₈ -alkyl, C₁ -C₈ -alkoxy, C₁ -C₈-alkylthio radical, such as the alkyl radicals having 1 to 8 carbonatoms and mentioned individually under R² and the corresponding alkoxyand alkylthio radicals, or C₅ -C₈ -cycloalkyl, phenyl, phenoxy and/orhalogen. Individual examples which may be mentioned are the tolyl,dimethylphenyl, triniethylphenyl, tert-butylphenyl, anisyl, naphthylradicals which additionally can carry up to 2 alkyl carbon atoms, andthe various biphenyl radicals, benzyl, α-methylbenzyl andα,α-dimethylbenzyl. Naturally the substituents in R¹ can only becombined in such a manner that no steric hindrance results. If R¹contains 3 substituents, more than 5 carbon atoms together should not becontained in the two o-positions.

Examples of suitable R¹ as divalent radical are the various phenyleneradicals, which are unsubstituted or carry 1 to 2 C₁ -C₈, in particularC₁ -C₃ -alkyl groups, or the various naphthylene radicals, which areunsubstituted or substituted by 1 to 4 C₁ -C₈ -, in particular C₁ -C₃-alkyl groups.

Examples of suitable radicals R² are non-aromatic hydrocarbon radicalshaving 1 to 18 carbon atoms, such as alkyl or cycloalkyl, furthermorearomatic radicals which, including aliphatic groups, have 6 to 18 carbonatoms, in which not more than 10 carbon atoms are part of an aromaticring system. The radicals R² preferably contain 4 to 12 and inparticular 6 to 10 carbon atoms. Individual examples of non-aromatichydrocarbon radicals which may be mentioned are alkyl, such as methyl,ethyl, the various propyl, butyl, pentyl, hexyl, octyl, decyl, dodecyl,hexadecyl and octadecyl radicals, and cycloalkyl having 5 to 10 carbonatoms, such as cyclopentyl, cyclohexyl, cycloheptyl and cyclohexylmethyl(i.e. not only the hydrogenated benzyl radical but also themethylcyclohexyl radical); further examples are C₈ -C₁₀ -aryl,-arylmethyl, -arylethyl and -arylisopropyl, in which the term aryl ineach case includes alkylaryl, carries not more 20, than three of thesubstituents mentioned under R¹ and including these has not more than 14carbon atoms.

If the radical R² is an alkyl radical, tertiary alkyl radicals having4-10 carbon atoms, such as tert-butyl, 2-methyl-2-butyl,2-methyl-2-pentyl, 2-ethyl-2-butyl are particularly preferred. Otherpreferred compounds are those in which R² is phenyl, benzyl,α-methylbenzyl or α,α-dimethylbenzyl.

The invention also relates to a process for the preparation of arylphosphonites of the formula V, in which A, additionally to theabovementioned meaning, can also be a direct bond, R¹ additionally tothe abovementioned meaning can also be unsubstituted phenyl or benzyl aswell as a nonaromatic hydrocarbon radical having 1 to 18 carbon atoms,such gas C₁ -C₁₈ -alkyl, and in compounds in which the two phenylradicals are linked by A can also be biphenylene or substituted orunsubstituted phenylene, and R² and R³ have the abovementioned meaning,which comprises first reacting in a first step a hydrocarbon halide R¹(--Hal)_(n), in which R¹ has the previously mentioned meaning, n is=1 or2 and the halogen has an atomic weight of at least 35, but is preferablychlorine or bromine, under Grignard conditions, that is, advantageouslywith intimate mixing, with at least molar amounts of magnesium to givethe corresponding Grignard compounds R¹ (MgHal)_(n) and reacting thesefurther in a second step with bisaryl halophosphonites of the formula VI(see formula sheet), in which R², R³ and Hal have the abovementionedmeaning, with the formation of bisaryl phosphonites V. The reaction canbe accelerated and the degree of conversion improved if the magnesium isused in a small excess. Advantageously, 1.1 to 1.5 equivalents ofmagnesium are converted per halogen atom. Exposure to ultrasound duringthe Grignard reaction can in some cases be advantageous. This means thatthis process is also suitable for the preparation of the compounds wheren= 1 and which fall under the exceptional formulation of the productclaim.

In the compounds of the formula VII Hal is preferably chlorine, inparticular when compounds are prepared in which the two phenyl radicalsare linked by A. This means that the process according to the inventionis also suitable for the preparation of those compounds containing thegroup A which have been disclosed in European Patent 337,784, U.S. Pat.Nos. 4,143,028 and 4,481,317. The cyclic diaryl chlorophosphites of theformula VI used as starting compounds are available in a simple mannerfrom corresponding bibphenols and phosphorus trichloride, for example bythe process described in European Laid-Open Application 312,915.

The first step of the process according to the invention, which can becarried out in any conventional manner, is preferably carried out in anaprotic, organic solvent, such as an ether, for example diethyl,dipropyl or diisopropyl ether, ethylene glycol dimethyl or -diethylether, diethylene glycol dimethyl or -diethyl ether, methyl tert-butylether, dioxane or tetrahydrofuran.

Since the Grignard compounds are sensitive to hydrolysis and oxidation,it may be advantageous to work under an inert gas atmosphere. However,such a procedure is not absolutely necessary for the reaction tosucceed. Particularly suitable inert gases are nitrogen and argon.

The reaction temperature is in general between 20° and 125° C., butpreferably between 30° and 70° C.

To prepare the compounds I or V, the solution or suspension of theGrignard compound is metered in the second step to the diarylhalophosphonite II or VI, which advantageously is diluted with an inert,aprotic solvent, for example hexane, toluene, xylene or one of theabove-mentioned ethers. The reactants in this step are combined slowly,in general between -30° C. and +30° C., but preferably between -20° C.and 20° C. As a rule, the reaction is exothermic; it can therefore beadvantageous to control the course of the reaction by cooling. The mostfavorable results are obtained by using the reactants in stoichiometricamounts. However, it is also possible to use one reactant in excess;however, this is in general not associated with particular advantages.Advantageously, the mixture is stirred until the reaction is complete,which is promoted by heating to 0° to 30° C. and then the precipitatedmagnesium halide is separated off. The solvents can be removed from thefiltrate in the usual manner, advantageously by distillation, inparticular under reduced pressure.

The ester halides II or VI which are required as starting materials canbe prepared in a simple manner from phosphorus trichloride and thecorresponding phenols (for example U.S. Pat. No. 4,739,000). The purityof the starting materials thus obtained is about 85-90% (according to ³¹P-NMR).

The products V can be separated from the crude products by any desiredmethod, but preferably by crystallization.

The synthesis of phosphonous esters by reaction of organometalliccompounds with chlorophosphonous diesters has been described by variousauthors. They point out in particular that high-purity chlorophosphonousesters must be used as starting materials (Houben-Weyl, Methoden derOrganischen Chemie (Methods of Organic Chemistry), volume 12/1, 329(1963)). Nevertheless, the yields of diaryl phosphonites were onlybetween about 33 and 75%. Since it is known that ester groups bound tothe phosphorus atom basically display the same behavior towardsorganometallic compounds as halogen atoms (Houben-Weyl, Methoden derOrganischen Chemie [Methods of Organic Chemistry], volume 12/1, 44(1963)) it could not be expected--even if in contrast to customarypractice no extremely pure chloroesters II or VII are used as startingmaterials--that the present process would provide the target compoundsin such a satisfactory manner and largely without any yield-reducingcompetition reactions.

It is particularly surprising that the products are available by theprocess according to the invention in such a high yield and purity,since, according to the details of Japanese Laid-Open Application57-46,993, phosphonous esters can in general only be obtained ineconomic yields by Grignard reactions if after the actual Grignardreaction various aftertreatment procedures with the addition ofauxiliaries and under inert gas atmosphere are carried out.

As a result, the present invention has made it possible to obtain anydesired substituted aryl phosphonites in a simple manner and with highyield and purity.

The invention finally relates to the use of the compounds of the formulaV by themselves or in combination with a phenolic antioxidant forstabilizing plastics, such as polycarbonates, preferably plasticsobtained by polymerization, such as polyolefins, in particularpolypropylene. The compounds of the formula I provide the plastics inthe molding compositions with improved stability to degradation bylight, oxygen and heat. However, the purity of the resulting crudereaction product (85-93% according to ³¹ P-NMR) is in most casessufficient for this application. In this case, they do not have to beisolated in pure form.

Accordingly, the present invention also relates to a plastic moldingcomposition comprising a thermoplastic or thermoset plastic and an arylphosphonite of the formula V in a ratio of (90 to 99.99):(0.01 to 10),in which n is 1 or 2, A is non-existent--i.e. the two rings carryhydrogen--or a divalent hydrocarbon bridge having 1 to 6 carbon atomswhich may be substituted by groups mentioned further below under R¹, oris a hetero atom such as oxygen or sulfur, cycloalkylidene having 4 to 8carbon atoms or phenylalkylidene having 7 to 12 carbon atoms, R¹ asmonovalent radical is a phenyl or benzyl radical, each of which carry 1to 3 substituents, or is α-methylbenzyl, α,α-dimethylbenzyl, naphthyl ora naphthyl radical carrying 1 to 5 substituents, in which thesubstituents can be identical or different and are a non-aromatichydrocarbon radical, an alkoxy radical, an alkylthio radical or adialkylamino radical, in which the alkyl radicals each have 1 to 8carbon atoms, aryl or aryloxy each having 6 to 10 carbon atoms orhalogen having an atomic number from 9 to 35, and as divalent radical anaphthylene radical which is unsubstituted or carries 1 to 4non-aromatic hydrocarbon radicals each having 1 to 8 carbon atoms assubstituents, or, if A is non-existent, a phenyl radical which isunsubstituted or substituted by up to two non-aromatic hydrocarbonradicals having 1 to 8 carbon atoms,

R² is a non-aromatic hydrocarbon radical of 1 to 18 carbon atoms, aryl,arylmethyl, arylethyl or arylisopropyl, in which the aryl in each casecontains 6 to 10 carbon atoms,

R³ is hydrogen or a group mentioned under R²,

where, in the compounds in which n is 1 and R¹ is phenyl, those areexcepted in which simultaneously

R² and R³ are each tert-butyl,

R² is tert-butyl and R³ is hydrogen,

R² is tert-octyl and R³ is methyl,

R² and R³ are each tert-octyl and

R² and R³ are each α,α-dimethylbenzyl.

Compounds of the formula I, in particular those containing nodialkylamino radicals, are preferred.

The plastic molding compound according to the invention contains athermoplastic or thermoset organic polymer, for example one of thefollowing:

1. Polymers of mono- and diolefins, for example polyethylene of high,medium or low density (which, if desired, can be crosslinked),polypropylene, polyisobutylene, poly-1-butene, polymethyl-1-pentene,polyisoprene or polybutadiene and polymers of cycloolefins, such ascyclopentene or norbornene.

2. Mixtures of the polymers mentioned under 1), for example ofpolypropylene with polyethylene or with polyisobutylene.

3. Copolymers of mono- and diolefins with one another or with othervinyl monomers, such as ethylene-propylene copolymers,propylene-1-butene copolymers, propyleneisobutylene copolymers,ethylene-1-butene copolymers, propylene-butadiene copolymers,isobutylene-isoprene copolymers, ethylene-alkyl acrylate copolymers,ethylene-alkyl methacrylate copolymers, ethylene-vinyl acetatecopolymers or ethylene-acrylic acid copolymers and salts thereof(ionomers), and terpolymers of ethylene with propylene and a diene, suchas hexadiene, dicyclopentadiene or ethylidenenorbornene.

4. Polystyrene.

5. Copolymers of styrene or α-methylstyrene with dienes or acrylicderivatives, such as styrene-butadiene, styrene-maleic anhydride,styrene-acrylonitrile, styrene-ethyl methacrylate,styrene-butadiene-ethyl acrylate, styrene-acrylonitrile-methyl acrylate;mixtures of high impact strength and composed of styrene copolymers andone other polymer, such as a polyacrylate, a diene polymer or anethylene-propylene-diene terpolymer; and block copolymers of styrene,such as styrene-butadiene-styrene, styrene-isoprene-styrene,styrene-ethylene/butylene-styrene or styrene-ethylene/propylene-styrene.

6. Graft copolymers of styrene, such as styrene onto polybutadiene,styrene and acrylonitrile onto polybutadiene (ABS), styrene and maleicanhydride onto polybutadiene, styrene and alkyl acrylates or alkylmethacrylates onto polybutadiene, styrene and acrylonitrile ontoethylene-propylene-diene terpolymers, styrene and acrylonitrile ontopoly(alkyl acrylates) or poly(alkyl methacrylates), styrene andacrylonitrile onto acrylatebutadiene copolymers, and mixtures thereofwith the copolymers mentioned under 5), which are known, for example, asso-called ABS, MBS, ASA or AES polymers.

7. Halogen-containing polymers, such as polychloroprene, chlorinatedrubber, chlorinated (CPE) or chlorosulfonated polyethylene,epichlorohydrin homo- and copolymers, in particular polymers ofhalogen-containing vinyl compounds, such as polyvinyl chloride (PVC),polyvinylidene chloride (PVDC), polyvinyl fluoride, polyvinylidenefluoride (PVDF); and the copolymers thereof, such as vinylchloride-vinylidene chloride, vinyl chloride-vinyl acetate or vinylidenechloride-vinyl acetate.

8. Polymers derived from α,β-unsaturated carboxylic acids andderivatives thereof, such as polyacrylates and polymethacrylates,polyacrylamides and polyacrylonitriles.

9. Copolymers of the monomers mentioned under 8) with one another orwith other unsaturated monomers, such as acrylonitrile-butadienecopolymers, acrylonitrile-alkyl acrylate copolymers,acrylonitrile-alkoxyacrylate copolymers, acrylonitrile-vinyl halidecopolymers or acrylonitrile-alkyl methacrylate-butadiene terpolymers.

10. Polymers derived from unsaturated alcohols and amines or acylderivatives or acetals thereof, such as polyvinyl alcohol, polyvinylacetate, stearate, benzoate, maleate, polyvinylbutyral, polyallylphthalate, polyallylmelamine.

11. Homo- and copolymers of cyclic ethers, such as polyethylene glycols,polyethylene oxide, polypropylene oxide or copolymers thereof withbisglycidyl ethers.

12. Polyacetals, such as polyoxymethylene (POM), and thosepolyoxymethylenes containing comonomers, such as ethylene oxide.

13. Polyphenylene oxides and sulfides.

14. Polyurethanes (PUR) derived on the one hand from polyethers,polyesters and polybutadienes having terminal hydroxyl groups and on theother hand from aliphatic or aromatic polyisocyanates and precursorsthereof (polyisocyanates-polyels prepolymers).

15. Polyamides and copolyamides derived from dismines and dicarboxylicacids and/or from aminocarboxylic acids or the corresponding lactams,such as nylon-4, nylon-6, nylon-6/6, nylon-6/10, nylon-11, nylon-12,poly-2,4,4-trimethylhexamethyleneterephthalamide,poly-m-phenyleneisophthalamide, and copolymers thereof with polyethers,such as with polyethylene glycol, polypropylene glycol orpolytetramethylene glycol.

16. Polyureas, polyamides and polyamidoimides.

17. Polyesters derived from dicarboxylic acids and diols and/or fromhydroxycarboxylic acids or the corresponding lactones, such aspolyethylene terephthalate, polybutylene terephthalate (PBTP),poly-1,4-dimethylolcyclohexane terephthalate,poly-(2,2-bis(4-hydroxyphenyl)propane) terephthalate,polyhydroxybenzoates, and block polyether esters derived frompolyethylene having terminal hydroxyl groups, dialcohols anddicarboxylic acids.

18. Polycarbonates (PC).

19. Polysulfones and polyether sulfones.

20. Crosslinked polymers derived on the one hand from aldehydes and onthe other hand from phenols, urea or melamine, such asphenol-formaldehyde, urea-formaldehyde and melamine-formaldehyde resins.

21. Drying and non-drying alkyd resins.

22. Unsaturated polyester resins derived from copolyesters of saturatedand unsaturated dicarboxylic acids with polyhydric alcohols, and vinylcompounds as cross-linking agents, as well as the halogen-containing,non-flammable modifications thereof.

23. Crosslinkable acrylic resins derived from substituted acrylicesters, such as from epoxy acrylates, urethane acrylates or polyesteracrylates.

24. Alkyd resins, polyester resins and acrylate resins crosslinked withmelamine resins, urea resins, polyisocyanates or epoxy resins.

25. Crosslinked epoxy resins derived from polyepoxides, for example frombis(glycidyl) ethers or from cycloaliphatic diepoxides.

26. Natural polymers, such as cellulose, natural rubber, gelatins andpolymer-homologous chemically modified derivatives thereof, such ascellulose acetates, propionates and butyrates, and the cellulose ethers,such as methylcellulose.

27. Mixtures of the abovementioned polymers, such as, for example,PP/EPDM, nylon-6/EPDM or ABS, PVC/EVA, PVC/ABS, PVC/MBS, PC/ABS,PBTP/ABS, PC/ASA, PC/PBT, PVC/CPE, PVD/acrylate, POM/thermoplastic PUR,POM/acrylate, POM/MBS, polyphenylene ether/high impact strengthpolystyrene (PPE/HIPS) PPE/nylon-6.6 and copolymers, PA/HDPE, PA/PP,PA/PPE.

28. Naturally occurring and synthetic organic materials which are puremonomers or mixtures of monomers, such as mineral oils, animal andvegetable fats, oils and waxes, or oils, fats and waxes based onsynthetic esters or mixtures of these materials.

29. Aqueous dispersions of natural or synthetic rubber.

The polymer is preferably a polyolefin, in particular polypropylene. Theamount of the polymer in the molding compound according to the inventionis 90 to 99.99, preferably 98 to 99.98% by weight.

The molding compound contains as stabilizer an aryl phosphonite of theformula I and, if necessary, a phenolic antioxidant.

The phenolic antioxidant is, for example, an ester of3,3-bis(3'-t-butyl-4'-hydroxyphenyl)butyric acid of the formula III (seeformula sheet), in which n is 1 or 2 and R⁴ is a C₁ -C₁₂ -dlkyl radical,if n is 1, and a C₁ -C₁₂ -alkylene radical, if n is 2. Preferably, R⁴ isa C₂ -C₄ -alkylene radical, in particular a C₂ -alkylene radical.

However, the phenolic antioxidant can also be an ester ofβ-(3,5-di-t-butyl-4-hydroxyphenyl)propionic acid of the formula IV (seeformula sheet), in which the alcohol component is a mono- to tetrahydricalcohol, such as methanol, octadecanol, 1,6-hexanediol, neopentylglycol, diethylene glycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl) isocyanurate, thiodiethylene glycol ordihydroxyethyloxamide.

The new stabilizers are incorporated in the organic polymers bygenerally customary methods. They can be incorporated, for example, byadmixing the compounds and, if necessary, further additives to the meltbefore or during the molding. They can also be incorporated by applyingthe dissolved or dispersed compounds directly to the polymer or admixingto a solution, suspension or emulsion of the polymer, if appropriatesubsequently allowing the solvent to evaporate. The amount to be addedto the polymers is 0.01 to 10, preferably 0.025 to 5, in particular 0.05to 1.0% by weight, relative to the material to be stabilized.

The new compounds can also be added in the form of a master batchcontaining these compounds, for example, in a concentration of 1 to 50,preferably 2.5 to 20% by weight, to the polymers which are to bestabilized.

In addition, the molding composition according to the invention can alsocontain other antioxidants, such as

1. alkylated monophenols, for example 2,6-di-t-butyl-4-methylphenol,-4-ethylphenol, -4-n-butylphenol, -4-i-butylphenol,2-t-butyl-4,6-dimethylphenol, 2,6-di-cyclopentyl-4-methylphenol,2-(α-methylcyclohexyl)-4,6-dimethylphenol,2,6-di-octadecyl-4-methylphenol, 2,4,6-tri-cyclohexylphenol,2,6-di-t-butyl-4-methoxymethylphenol;

2. alkylated hydroquinones, such as 2,5-di-t-butyl- and2,5-di-t-amylhydroquinone, 2,6-di-t-butyl-4-methoxyphenol and2,6-diphenyl-4-octadecyloxyphenol;

3. hydroxylated thiodiphenyl ethers, such as2,2'-thio-bis(6-t-butyl-4-methylphenol) and -(4-octylphenol) and4,4'-thio-bis(6-t-butyl-3-methylphenol) and -(6-t-butyl-2-methylphenol);

4. alkylidene bisphenols, such as2,2'-methylene-bis(6-t-butyl-4-methylphenol),-(6-t-butyl-4-ethylphenol), -[4-methyl-6-(α-methylcyclohexyl)phenol],-(4-methyl-6-cyclohexylphenol), -(6-nonyl-4-methylphenol),-(4,6-di-t-butylphenol), -[6-(α-methylbenzyl)-4-nonylphenol],-[6-(α,α-dimethylbenzyl)-4-nonylphenol],4,4'-methylene-bis(2,6-di-t-butylphenol) and-(6-t-butyl-2-methylphenol), 2,2'-ethylidene-bis(4,6-di-t-butylphenol)and -(6-t-butyl-4-isobutylphenol), 1,1-bis- and1,1,3-tris(5-t-butyl-4-hydroxy-2-methylphenyl)butane,2,6-di(3-t-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol,1,1-bis(5-t-butyl-4-hydroxy-2-methylphenyl)-3-n-dodecylmercaptobutane,di(3-t-butyl-4-hydroxy-5-methylphenyl)dicyclopentadiene;

5. benzyl compounds, such asdi[2-(3'-t-butyl-2-hydroxy-5'-methylbenzyl)-6-t-butyl-4-methylphenyl]terephthalate,1,3,5-tri(3,5-di-t-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene,di(3,5-di-t-butyl-4-hydroxybenzyl) sulfide, isooctyl3,5-di-t-butyl-4-hydroxybenzylmercapto acetate,bis(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) dithiolterephthalate,1,3,5-tris(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate,1,3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate,dioctadecyl 3,5-di-t-butyl-4-hydroxybenzylphosphonate and the calciumsalt of monoethyl 3,5-di-t-butyl-4-hydroxybenzylphosphonate;

6. acylaminophenols, such as 4-hydroxylaur- and -stearanilide,2,4-bis(octylmercapto)-6-(3,5-di-t-butyl-4-hydroxyanilino)-s-triazineand octyl N-(3,5-di-t-butyl-4-hydroxyphenyl)carbamate;

7. esters of β-(5-t-butyl-4-hydroxy-3-methylphenyl) propionic acid withmono- or polyhydric alcohols, such as with methanol, octadecanol,1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol,pentaerythritol, tris(hydroxyethyl) isocyanurate, thiodiethylene glycolor dihydroxyethyloxamide;

8. amides of β-(3,5-di-t-butyl-4-hydroxyphenyl)propionic acid, such asN,N'-di(3,5-di-t-butyl-4-hydroxyphenylpropionyl)trimethylenediamine,-hexamethylenediamine and -hydrazine.

In addition, the molding composition according to the invention cancontain further additives, such as

1. UV absorbers and light stabilizers, for example

1.1 2-(2'-hydroxymethyl)benzotriazoles, such as the 5'-methyl,3',5'-di-t-butyl, 5'-t-butyl, 5'-(1,1,3,3-tetramethylbutyl),5-chloro-3',5'-di-t-butyl, 5-chloro-3'-t-butyl-5'-methyl,3'-sec.-butyl-5'-t-butyl, 4'-octoxy, 3',5'-di-t-amyl,3',5'-bis(α,α-dimethylbenzyl) derivative;

1.2 2-hydroxybenzophenones, such as the 4-hydroxy, 4-methoxy, 4-octoxy,4-decyloxy, 4-dodecyloxy, 4-benzyloxy, 4,2',4'-trihydroxy,2'-hydroxy-4,4'-dimethoxy derivative;

1.3 esters of substituted or unsubstituted benzoic acids, such as phenylsalicylate, 4-t-butylphenyl salicylate, octylphenyl salicyalate [sic],dibenzoylresorcinol, bis(4-t-butylbenzoyl)resorcinol, benzoylresorcinol, 2,4-di-t-butylphenyl 3,5-di-t-butyl-4-hydroxybenzoate,hexadecyl 3,5-di-t-butyl-4-hydroxybenzoate;

1.4 acrylates, such as ethyl or isooctyl α-cyano-β,β-diphenylacrylate,methyl α-carbomethoxy- and α-carbomethoxy-p-methoxycinnamate, methyl orbutyl α-cyano-p-methyl-p-methoxycinnamate,N-(β-carbomethoxy-β-cyanovinyl)-2-methylindoline;

1.5 nickel compounds, such as nickel complexes of2,2'-thiobis[4-(1,1,3,3-tetramethylbutyl)phenol], such as the 1:1 or 1:2complex, if desired with additional ligands, such as n-butylamine,triethanolamine or N-cyclohexyldiethanolamine, nickel alkyldithiocarbamates, nickel salts of monoalkyl4-hydroxy-3,5-di-t-butylbenzylphosphonates, such as those of the methylor ethyl ester, nickel complexes of ketoximes, such as those of2-hydroxy-4-methylphenylundecylketonoxime, nickel complexes of1-phenyl-4-lauroyl-5-hydroxypyrazole, if desired with additionalligands;

1.6 sterically hindered antines, such as

1.6.1 bis(2,2,6,6-tetramethylpiperidyl) sebacate,bis(2,2,6,6-tetramethylpiperidyl) glutarate andbis(2,2,6,6-tetramethylpiperidyl) succinate,bis(1,2,2,6,6-pentamethylpiperidyl) sebacate,bis(1,2,2,6,6-pentamethylpiperidyl) glutarate- andbis(1,2,2,6,6-pentamethylpiperidyl) succinate, 4-stearyloxy- and4-stearoyloxy-2,2,6,6-tetramethylpiperidine, 4-stearyloxy- and4-stearoyloxy-1,2,2,6,6-pentamethylpiperidine,2,2,6,6-tetramethylpiperidyl behenate, 1,2,2,6,6-pentamethylpiperidylbehenate,2,2,4,4-tetramethyl-7-oxa-3,20-diazadispiro-[5.1.11.2]heneicosan-2'-one,2,2,3,4,4-pentamethyl-7-oxa-3,20-diazadispiro[5.1.11.2]heneicosan-2'-one,2,2,4,4-tetramethyl-3-acetyl-7-oxa-3,20-diazadispiro[5.1.11.2]heneicosan-2'-one,2,2,4,4-tetramethyl-7-oxa-3,20-diaza-20-(β-lauryloxycarbonylethyl)-2'-oxo-dispiro-[5.1.11.2]heneicosane,2,2,3,4,4-pentamethyl-7-oxa-3,20-diaza-20-(β-lauryloxycarbonylethyl)-2'-oxo-dispiro[5.1.11.2]heneicosane,2,2,4,4-tetrα-methyl-3-acetyl-7-oxa-3,20-diaza-20-(β-lauryloxycarbonylethyl)-2'-oxo-dispiro-[5.1.11.2]heneicosane,1,1',3,3',5,5'-hexahydro-2,2',4,4',6,6'-hexaaza-2,2',6,6'-bismethano-7,8-dioxo-4,4'-bis(1,2,2,6,6-pentamethyl-4-piperidyl)biphenyl,N,N',N",N"'-tetrakis{2,4-bis[N-(2,2,6,6-tetramethyl-4-piperidyl)butylamino]-1,3,5-triazin-6-yl}-4,7-diazadecane-1,10-diamine,N,N',N",N"'-tetrakis{2,4-bis[N-(1,2,2,6,6-pentamethyl-4-piperidyl)butylamino]-1,3,5-triazin-6-yl}-4,7-diazadecane-1,10-diamine,N,N',N",N"'-tetrakis{2,4-bis[N-(2,2,6,6-tetramethyl-4-piperidyl)methoxypropylamino]-1,3,5-triazin-6-yl}-4,7-diazadecane-1,10-diamine,N,N',N",N"'-tetrakis{2,4-bis[N-(1,2,2,6,6-pentamethyl-4-piperidyl)methoxypropylamino]-1,3,5-triazin-6-yl}-4,7-diazadecane-1,10-diamine,bis(1,2,2,6,6-pentamethylpiperidyl)-n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate, tris(2,2,6,6-tetramethyl-4-piperidyl) nitrilotriacetate,tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylicacid, 1,1'-(1,2-ethanediyl)bis(3,3,5,5-tetramethylpiperazinone);

1.6.2 poly-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,8-diazadecylene,condensation product of1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine with succinicacid, condensation product ofN,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine with4-tert-octylamino-2,6-dichloro-1,3,5-s-triazine, condensation product ofN,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine with4-morpholino-2,6-dichloro-1,3,5-triazine.

In many cases, a combination of the compounds according to the inventionwith the compounds mentioned under 1.6.1 proves especially advantageous.

1.7 oxamides, such as 4,4'-di-octyloxyoxanilide,2,2'-di-octyloxy-5,5'-di-t-butyloxanilide,2,2'-didodecyloxy-5,5'-di-t-butyloxanilide, 2-ethoxy-2'-ethyloxanilide,N,N'-bis(3-dimethylaminopropyl)oxamide,2-ethoxy-5-t-butyl-2'-ethyloxanilide and its mixture with2-ethoxy-2'-ethyl-5,4-di-t-butyloxanilide, mixtures of o- and p-methoxy-and -ethoxy-disubstituted oxanilides;

2. metal deactivators, such as N,N'-diphenyloxamide,N-salicylal-N'-salicyloylhydrazine, N,N'-bis-salicyloylhydrazine,N,N'-bis(3,5-di-t-butyl-4-hydroxyphenylpropionyl)hydrazine,3-salicyloylamino-1,2,3-triazole, bis(benzylidene)oxalic dihydrazide;

3. phosphites and phosphonites, for example triphenyl phosphite,diphenylalkyl phosphites, phenyl dialkyl phosphites, tris(nonylphenyl)phosphite, trilauryl phosphite, trioctadecyl phosphite, distearylpentaerythrityl diphosphite, tris(2,4-di-t-butylphenyl) phosphite,diisodecyl pentaerythrityl diphosphite, bis(2,4-di-t-butylphenyl)pentaerythrityl diphosphite, tristearyl sorbityl triphosphite,tetrakis-(2,4-di-t-butylphenyl)-4,4'-biphenylene diphosphonite,3,9-bis(2,4-di-t-butylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane,tris(2-t-butyl-4-thio(2'-methenyl-4'-hydroxy-5'-t-butyl(phenyl-5-methenyl)phenylphosphite.

4. peroxide-destroying compounds, such as esters of β-thiodipropionicacid, for example the lauryl, stearyl, myristyl or tridecyl ester,mercaptobenzimidazole, the zinc salt of 2-mercaptobenzimidazole, zincalkyl dithiocarbamates, dioctadecyl sulfide, dioctadecyl monosulfide,pentaerythritol tetrakis-(β-dodecylmercapto)propionate;

5. basic co-stabilizers, such as melamine, polyvinylpyrrolidone,dicyandiamide, triallylcyanurate, urea derivatives, hydrazinederivatives, amines, polyamines, polyurethanes, alkali metal salts andalkaline earth metal salts of higher fatty acids or phenolates, forexample calcium stearate, zinc stearate and magnesium stearate, sodiumricinoleate, potassium palmitate, antimony catecholate or tincatecholate, hydroxides and oxides of alkaline earth metals or ofaluminum, for example CaO, MgO, ZnO;

6. nucleating agents, such as 4-t-butylbenzoic acid, adipic acid,diphenylacetic acid, dibenzylidenesorbitol;

7. fillers and reinforcing agents, such as calcium carbonate, silicates,glass fibers, asbestos, talc, kaolin, mica, barium sulfate, metal oxidesand metal hydroxides, carbon black, graphite;

8. other additives, such as plasticizers, lubricants, emulsifiers,pigments, optical brighteners, flame retardants, antistats, blowingagents.

The various additional additives of the abovementioned groups 1 to 6 areadded to the polymers to be stabilized in an amount of 0.01 to 10,preferably 0.01 to 5, % by weight, relative to the total weight of themolding composition. The relative amount of the additives from groups 7and 8 is in general 1 to 80, preferably 10 to 50, % by weight, relativeto the total molding composition.

The organic polymers stabilized according to the invention can beapplied in various forms, for example as films, fibers, ribbons,profiles or as binders for paints, adhesives or putties.

In the examples 1 to 24 which follow, the compounds obtained accordingto the invention were crystallized using certain solvent mixtures. Theratios given are by volume. By changing the mixing ratios, it may bepossible to achieve even better results.

Examples for the preparation of diaryl phosphonites

General Procedure for Compounds of the Formula I

Under a nitrogen atmosphere and with the exclusion of moisture, 250 mmolof organobromo compound and 250 mmol (=6.1 g) of Mg turnings in 170 mlof tetrahydrofuran were used to prepare the corresponding Grignardcompound.

The solution or suspension obtained was then metered into the solutionof 250 mmol of diaryl chlorophosphonite in 150 ml ofn-hexane/tetrahydrofuran (2:1) at an internal temperature of -20° to-10° C. with vigorous stirring over a period of 30-40 min. The reactionmixture was then allowed to warm to room temperature, and stirring wascontinued for 2.5 hours to complete the reaction. After the precipitatedMg salt had been filtered off, the solvent was distilled off first inthe vacuum of a water pump and then in a high vacuum, and the colorlessor light beige residue obtained was powdered and dried in a high vacuum.

The amount of product in the crude materials was determined by ³¹ P-NMRspectroscopy. It was in general between 85 and 93% (of the totalproduct). To characterize the product, it was crystallized in the casesmentioned from acetonitrile/acetone mixtures.

1) Bis(2'4'-di-tert-butylphenyl) (2,4,6-trimethyl-1-phenyl)phosphonite:starting from 49.7 g of bromomesitylene and 119.3 g ofbis(2,4-di-tert-butylphenyl) chlorophosphonite, 140 g of colorlessmaterial of a softening point of about 60° C. containing 90% of theabove compound were obtained. Crystallization from acetonitrile/acetone(15:1) gave colorless crystals of melting point 95°-97° C.; [³¹ P-NMR:δ_(CDCl).sbsb.3 =168.4 ppm).

    ______________________________________                                        C.sub.37 H.sub.53 O.sub.2 P                                                            Calculated:                                                                             79.24%  C,  9.52% H,  5.52% P                              (560.8)  Found:    78.9%   C,  9.7%  H,  5.3%  P.                             ______________________________________                                    

2) Bis(2',4'-di-tert-butylphenyl) (2,4,5-trimethyl-1-phenyl)phosphonite:starting from 49.7 g of 5-bromo-1,2,4-trimethylbenzene and 119.3 g ofbis(2,4-di-tertbutylphenyl) chlorophosphonite, 140 g of a yellowishmaterial containing 93% of the above compound were obtained. Softeningpoint about 30°-35° C.; [³¹ P-NMR: δ_(CDCl).sbsb.3 =155.4 ppm]. C₃₇ H₅₃O₂ P (560.8).

3) Bis(2',4'-di-tert-butylphenyl) (4-tert-butylphenyl)phosphonite:starting from 53.3 g of p-bromo-tert-butylbenzene and 119.3 g ofbis(2,4-di-tert-butylphenyl) chlorophosphonite, about 140 g of colorlessmaterial containing 90% of the above compound were obtained.Crystallization of the crude product from acetonitrile/acetone (15:2)gave colorless crystals of melting point 115°-117° C.; [³¹ P-NMR:δ_(CDCl).sbsb.3 =155.9 ppm].

    ______________________________________                                        C.sub.38 H.sub.55 O.sub.2 P                                                            Calculated:                                                                             79.4%   C,  9.64% H,  5.38% P                              (574.82) Found:    79.8%   C,  9.9%  H,  5.0%  P.                             ______________________________________                                    

4) Bis(2'-tert-butylphenyl) (4-tert-butylphenyl)-phosphonite: startingfrom 53.3 g of p-bromo-tert-butylbenzene and 91.2 g ofbis(2-tert-butylphenyl) chlorophosphonite, about 115 g of viscous resincontaining 85% of the above compound were obtained. Crystallization ofthe crude product from acetonitrile/acetone (2:1) gave colorlesscrystals of melting point 95°-97° C.; [³¹ P-NMR: δ_(CDCl).sbsb.3 =155.9ppm].

    ______________________________________                                        C.sub.30 H.sub.39 O.sub.2 P                                                            Calculated:                                                                             77.89%  C,  8.49% H,  6.69% P                              (462.61) Found:    77.5%   C,  8.7%  H,  6.5%  P.                             ______________________________________                                    

5) Bis(2',4'-di-tert-butylphenyl) 1-naphthylphosphonite: starting from51.8 g of 1-bromonaphthalene and 119.3 g of bis(2,4-di-tert-butylphenyl)chlorophosphonite, about 142 g of a colorless solid of softening point50°-55° C. containing 91% of the above compound were obtained.Crystallization of the crude product from acetonitrile/acetone (5:1)gave colorless crystals of melting point 125°-127° C.; [³¹ P-NMR:δ_(CDCl).sbsb.3 =158.1 ppm].

    ______________________________________                                        C.sub.38 H.sub.49 O.sub.2 P                                                            Calculated:                                                                             80.24%  C,  8.68% H,  5.44% P                              (568.77) Found:    80.5%   C,  8.5%  H,  5.3%  P.                             ______________________________________                                    

6) Bis(2',4'-di-tert-butylphenyl) (4-methyl-1-naphthyl)phosphonite:starting from 55.27 g of 1-bromo-4-methylnaphthalene and 119.3 g ofbis(2,4-di-tert-butylphenyl) chlorophosphonite, about 140 g of a beigematerial containing 93% of the above compound were obtained.Crystallization from acetone gave colorless crystals of melting point145°-146° C.; [³¹ P-NMR: δ_(CDCl).sbsb.3 =159.0 ppm].

    ______________________________________                                        C.sub.39 H.sub.51 O.sub.2 P                                                            Calculated:                                                                             80.37%  C,  8.82% H,  5.31% P                              (582.80) Found:    80.7%   C,  9.1%  H,  5.1%  P.                             ______________________________________                                    

7) Bis(2'-tert-butylphenyl) (4-methyl-1-naphthyl)phosphonite: startingfrom 55.27 g of 1-bromo-4-methylnaphthalene and 91.2 g ofbis(2-tert-butylphenyl) chlorophosphonite, about 110 g of a yellow resincontaining 90% of the above compound were obtained; [³¹ P-NMR: δ_(CDCl)₃ =158.4 ppm]. C₃₁ H₃₅ O₂ P (470.6).

8) Bis(2',4'-di-tert-butylphenyl) (2-methyl-1-naphthyl)phosphonite:starting from 55.27 g of 1-bromo-2-methylnaphthalene and 119.3 g ofbis(2,4-di-tert-butylphenyl) chlorophosphonite, about 140 g of ayellowish material containing 90% of the above compound were obtained.Crystallization from acetone/acetonitrile (2:1) gave colorless crystalsof melting point 157°-159° C.; [³¹ P-NMR: δ_(CDCl).sbsb.3 =164.4 ppm].

    ______________________________________                                        C.sub.39 H.sub.51 O.sub.2 P                                                            Calculated:                                                                             80.37%  C,  8.82% H,  5.31% P                              (582.80) Found:    79.9%   C,  9.1%  H,  5.1%  P.                             ______________________________________                                    

9) Bis(2',4'-di-tert-butylphenyl) 2-naphthylphosphonite: starting from51.8 g of 2-bromonaphthalene and 119.3 g of bis(2,4-di-tert-butylphenyl)chlorophosphonite, about 143 g of a colorless solid containing 94% ofthe above compound were obtained. Crystallization of the crude productfrom acetonitrile/acetone (9:1) gave colorless crystals of melting point133°-135° C.; [³¹ P-NMR: δ_(CDCl).sbsb.3 =155.0 ppm].

    ______________________________________                                        C.sub.38 H.sub.49 O.sub.2 P                                                            Calculated:                                                                             80.24%  C,  8.68% H,  5.44% P                              (568.77) Found:    80.4%   C,  8.9%  H,  5.2%  P.                             ______________________________________                                    

10) Bis(2',4'-di-tert-butylphenyl) (6-methoxy-2-naphthyl)phosphonite:starting from 59.3 g of 2-bromo-6-methoxynaphthalene and 119.3 g ofbis(2,4-di-tert-butylphenyl) chlorophosphonite, 147 g of a colorlesssolid containing 93% of the above compound were obtained.Crystallization from acetone gave colorless crystals of melting point146°-148° C.; [³¹ P-NMR: δ_(CDCl).sbsb.3 =155.9 ppm].

    ______________________________________                                        C.sub.39 H.sub.51 O.sub.3 P                                                            Calculated:                                                                             78.22%  C,  8.58% H,  5.17% P                              (598.80) Found:    78.6%   C,  8.3%  H,  4.8%  P.                             ______________________________________                                    

11) Bis(2',4'-di-tert-butylphenyl) (4-methoxyphenyl)phosphonite:starting from 46.75 g of 4-bromoanisole and 119.3 g ofbis(2,4-di-tert-butylphenyl) chlorophosphonite, about 137 g of acolorless material of softening point 50° C. containing 93% of the abovecompound were obtained; [³¹ P-NMR: δ_(CDCl).sbsb.3 =155.8 ppm].

    ______________________________________                                        C.sub.35 H.sub.49 O.sub.3 P                                                            Calculated:                                                                             76.60%  C,  9.00% H,  5.64% P                              (548.74) Found:    76.9%   C,  9.2%  H,  5.2%  P.                             ______________________________________                                    

12) Bis(2',4'-di-tert-butylphenyl) 4-biphenylphosphonite: starting from58.3 g of 4-bromobiphenyl and 119.3 g of bis(2,4-di-tert-butylphenyl)chlorophosphonite, about 148 g of a colorless powder having a softeningpoint of about 90° C. and containing 90% of the above compound wereobtained [³¹ P-NMR : δ_(CDCl).sbsb.3 =154.8 ppm]. Crystallization fromacetonitrile/acetone (10:1) gave colorless crystals of melting point103°-105° C.

    ______________________________________                                        C.sub.40 H.sub.51 O.sub.2 P                                                            Calculated:                                                                             80.77%  C,  8.64% H,  5.20% P                              (594.81) Found:    81.2%   C,  8.8%  H,  4.9%  P                              ______________________________________                                    

13) Bis(2',4'-di-tert-butylphenyl) 4-bromophenylphosphonite: startingfrom 59 g of 1,4-dibromobenzene and 119.3 g of bis(2,4-di-tert-butylphenyl) chlorophosphonite, about 145 g of an amorphoussolid of softening point 80° C. containing about 85% of the abovecompound [³¹ P-NMR: δ_(CDCl).sbsb.3 =152.4 ppm] were obtained. C₃₄ H₄₆BrO₂ P (597.61).

14) Tetra(2',4'-di-tert-butylphenyl) 1,4-phenylenediphosphonite: theabovementioned procedure was modified, and 500 mmol (=12.2 g) ofmagnesium and 500 mmol (=238 g) of bis(2,4-di-tert-butylphenyl)chlorophosphonite were used instead of 250 mmol per 250 mmol (=59 g) of1,4-dibromobenzene to give about 200 g of the above compound of meltingpoint 178°-180° C. from acetone [³¹ P-NMR: δ_(CDCl).sbsb.3 =153.1 ppm].

    ______________________________________                                        C.sub.62 H.sub.88 O.sub.4 P.sub.2                                                      Calculated:                                                                             77.62%  C,  9.24% H,  6.45% P                              (959.32) Found:    78.0%   C,  9.0%  H,  6.2%  P.                             ______________________________________                                    

15) Tetra(2',4'-di-tert-butylphenyl) 1,3-phenylenediphosphonite: Example14 was repeated, except that 1,3-dibromobenzene was used, giving about240 g of a beige solid containing about 70% of the above compound [³¹P-NMR: δ_(CDCl).sbsb.3 =154.25 ppm] and a softening point of 70°-75° C.

General procedure for compounds of the formula V in which the two phenylradicals are linked by A.

At first the procedure adopted was analogous to that in the preparationof compounds II, except that 250 mmol of the respective cyclicchlorophosphonite diester of the formula VI in 200 ml oftetrahydrofuran/n-hexane (2:1) were metered in at an internaltemperature of -10° to 0° C. Stirring at 0° C. was then continued for 1hour and at room temperature for 2.5 hours. After the precipitatedmagnesium halide had been filtered off and washed with 250 ml oftetrahydrofuran/n-hexane (4:1), the solvent was distilled off first in avacuum of water pump and then in a high vacuum. The crude products werepurified by crystallization.

16.4,8-Di-tert-butyl-2,10-dimethyl-6-(11-naphthyl)-12H-dibenzo[d,g][1,3,2]dioxaphosphocine:starting from 51.8 g of 1-bromonaphthalene and 101.2 g of4,8-di-tert-butyl-6-chloro-2,10-dimethyl-12H-dibenzo[d,g][1,3,2]dioxaphosphocine,94.3 g (=76%) of the above compound were obtained from acetone in theform of colorless crystals of melting point 251°-253° C.

    ______________________________________                                        C.sub.33 H.sub.37 O.sub.2 P                                                            Calculated:                                                                             79.81%  C,  7.50% H,  6.23% P                              (496.62) Found:    79.4%   C,  7.8%  H,  6.0%  P.                             ______________________________________                                    

17.4,8-Di-tert-butyl-2,10-diethyl-6-(11-naphthyl)-12H-dibenzo[d,g][1,3,2]dioxaphosphocine:starting from 51.8 g of 1-bromonaphthalene and 108.2 g of4,8-di-tert-butyl-6-chloro-2,10-diethyl-12H-dibenzo(d,g)[1,3,2]dioxaphosphocine,106.2 g (=81%) of the above compound were obtained from acetonitrile inthe form of colorless crystals of melting point 206°-208° C.

    ______________________________________                                        C.sub.35 H.sub.41 O.sub.2 P                                                            Calculated:                                                                             80.12%  C,  7.87% H,  5.90% P                              (524.68) Found:    79.5%   C,  7.8%  H,  5.7%  P.                             ______________________________________                                    

18.4,8-Di-tert-butyl-2,10-diethyl-6-(2'-naphthyl)-12H-dibenzo[[d,g][1,3,2]dioxaphosphocine:starting from 51.8 g of 2-bromonaphthalene and 108.2 g of4,8-di-tert-butyl-6-chloro-2,10-diethyl-12H-dibenzo[d,g][1,3,2]dioxaphosphocine,109 g (=83%) of the above compound were obtained from acetonitrile inthe form of colorless crystals of melting point 222°-224° C.

    ______________________________________                                        C.sub.35 H.sub.41 O.sub.2 P                                                            Calculated:                                                                             80.12%  C,  7.87% H,  5.90% P                              (524.68) Found:    79.9%   C,  8.1%  H,  5.7%  P.                             ______________________________________                                    

19.4,8-Di-tert-butyl-2,10-dimethyl-6-(4'-methyl-1'-naphthyl)-12H-dibenzo[d,g][1,3,2]dioxaphosphocine:starting from 55.27 g of 1-bromo-4-methylnaphthalene and 101.2 g of4,8-di-tert-butyl-6-chloro-2,10-dimethyl-12H-dibenzo[[d,g][1,3,2]dioxaphosphocine,95.7 g (=75%) of the above compound were obtained fromacetone/dichloromethane (5:1) in the form of colorless crystals ofmelting point 273°-276° C.

    ______________________________________                                        C.sub.34 H.sub.39 O.sub.2 P                                                            Calculated:                                                                             79.97%  C,  7.70% H,  6.06% P                              (510.66) Found:    79.3%   C,  7.8%  H,  6.1%  P.                             ______________________________________                                    

20.4,8-Di-tert-butyl-2,10-diethy-6-(4'-methyl-1'-naphthyl)-12H-dibenzo[d,g][1,3,2]dioxaphosphocine:starting from 55.27 g of 1-bromo-4-methylnaphthalene and 108.2 g of4,8-di-tert-butyl-6-chloro-2,10-diethyl-12H-dibenzo[d,g][1,3,2]dioxaphosphocine,100 g (=74%) of the above compound were obtained from acetone in theform of colorless crystals of melting point 258°-260° C.

    ______________________________________                                        C.sub.36 H.sub.43 O.sub.2 P                                                            Calculated:                                                                             80.26%  C,  8.04% H,  5.74% P                              (538.71) Found:    79.9%   C,  8.3%  H,  5.4%  P.                             ______________________________________                                    

21.4,8-Di-tert-butyl-2,10-diethyl-6-(4'-biphenyl)-12H-dibenzo[d,g][1,3,2]dioxaphosphocine:starting from 58.3 g of 4-bromobiphenyl and 108.2 g of4,8-di-tert-butyl-6-chloro-2,10-diethyl-12H-dibenzo[d,g][1,3,2]dioxaphosphocine,103.3 g (=75%) of the above compound were obtained from acetonitrile inthe form of colorless crystals of melting point 170°-172° C.

    ______________________________________                                        C.sub.37 H.sub.43 O.sub.2 P                                                            Calculated:                                                                             80.70%  C,  7.87% H,  5.62% P                              (550.72) Found:    80.2%   C,  7.9%  H,  5.4%  P.                             ______________________________________                                    

22.4,8-Di-tert-butyl-2,10-diethyl-6-(2',4',5'-trimethyl-1'-phenyl)-12H-dibenzo[d,g][1,3,2]dioxaphosphocine:starting from 49.7 g of 5-bromo-1,2,4-trimethylbenzene and 108.2 g of4,8-di-tert-butyl-6-chloro-2,10-diethyl-12H-dibenzo[d,g)[1,3,2]dioxaphosphocine,113.7 g (=88%) of the above compound were obtained fromacetonitrile/acetone (1:1) in the form of colorless crystals of meltingpoint 198°-200° C.

    ______________________________________                                        C.sub.34 H.sub.45 O.sub.2 P                                                            Calculated:                                                                             79.03%  C,  8.77% H,  6.0%  P                              (516.70) Found:    79.3%   C,  8.7%  H,  5.8%  P.                             ______________________________________                                    

23.4,4'-Biphenylene-bis[4,8-di-tert-butyl-2,10-diethyl-6-yl-12H-dibenzo[d,g][1,3,2]dioxaphosphocine]:the general procedure was modified, and 200 mmol (=62.4 g) of4,4'-dibromobiphenyl were subjected to a Grignard reaction with 600 mmol(=14.6 g) of magnesium turnings in 300 ml of tetrahydrofuran withexposure to ultrasound (40 kHz) and then reacted with 400 mmol (=173.2g) of4,8-di-tert-butyl-6-chloro-2,10-diethyl-12H-dibenzo[d,g][1,3,2]dioxaphosphocinein 250 ml of tetrahydrofuran. After evaporation of the solvent, about190 g of a solid remained containing (by ³¹ P-NMR) 73% of the abovecompound (³¹ P-NMR: σ_(CDCl).sbsb.3 =163.7 ppm). Colorless crystals ofmelting point 320° C. (decomposition) were obtained from acetone.

    ______________________________________                                        C.sub.62 H.sub.75 O.sub.4 P.sub.2                                                      Calculated:                                                                             78.61%  C,  8.08% H,  6.54% P                              (947.23) Found:    78.3%   C,  8.2%  H,  6.3%  P.                             ______________________________________                                    

24.4,4'-Biphenylene-bis[4,8-di-tert-butyl-2,10-dimethyl-6-yl-12H-dibenzo[d,g][1,3,2]dioxaphosphocine]:the procedure was analogous to that of the previous example, except thatthe Grignard reagent was reacted with 400 mmol (=162 g) of4,8-di-tert-butyl-6-chloro-2,10-dimethyl-12H-dibenzo[d,g][1,3,2]dioxaphosphocine.About 180 g of a solid remained, containing (by ³¹ P-NMR) 72% of theabove compound (³¹ P-NMR: σ_(CDCl).sbsb.3 =163.9 ppm). Colorlesscrystals of melting point 306°-310° C. (decomposition) were obtainedfrom acetone.

    ______________________________________                                        C.sub.58 H.sub.68 O.sub.4 P.sub.2                                                      Calculated:                                                                             78.17%  C,  7.69% H,  6.97% P                              (891.12) Found:    77.8%   C,  7.8%  H,  6.7%  P.                             ______________________________________                                    

II. WORKING EXAMPLES

The phosphonites according to the invention listed below were used forthe experiments.

25 and 31: Bis(2',4'-di-tert-butylphenyl) 4-biphenylphosphoniteaccording to Example 12, contained about 98% by ³¹ P-NMR

26 and 32: Bis(2',4'-di-tert-butylphenyl) β-naphthylphosphoniteaccording to Example 9, contained about 98% by ³¹ P-NMR

27 and 33: Tetra(2',4'-di-tert-butylphenyl) 1,4-phenylenediphosphoniteaccording to Example 14, contained about 95% by ³¹ P-NMR

28 and 34: Bis(2',4'-di-tert-butylphenyl)(4-methyl-1-naphthyl)phosphonite according to Example 6

29 and 35: Bis(2,4-di-tert-butylphenyl) 2-methylnaphthylphosphoniteaccording to Example 8

30 and 36: Bis(2,4-di-tert-butylphenyl)(2-methoxy-6-naphthyl)phosphonite according to Example 10

25 TO 30 AND COMPARATIVE EXAMPLES A TO C

100.0 g of unstabilized polypropylene powder (density: 0.903 g/cm³ ;melt flow index MFI 230/5: 4 g/10 min) were mixed with 0.1 g of Castearate as acid acceptor and the amounts of phosphorus compound listedin the tables and extruded several times by means of a laboratoryextruder (short-compression zone screw, diameter of screw 20 mm; length400 mm, length of nozzle 30 mm, diameter [lacuna] mm; speed: 125 rpm;temperature program: 200°/230°/230° C.). After the 1st, 5th and 10thpass, samples were removed from the granules and used to measure themelt flow index according to DIN 53 735 and the yellowness as yellownessindex according to ASTM D 1925-70. In addition, the granules of the 1stpass were used to produce extruded sheets of the dimensions 60×60×1 mm,and the yellowness was measured immediately and after hot storage (7days at 100° C.).

The results are listed in Tables 1, 2 and 5.

31 TO 36 AND COMPARATIVE EXAMPLES D TO F

100.0 g of unstabilized polypropylene powder (density: 0.903 g/cm³ ;melt flow index MFI 230/5: 4 g/10 min) were mixed with 0.1 g of Castearate as acid acceptor and 0.05 g of ethylene glycolbis(3,3-bis(3'-t-butyl-4'-hydroxyphenyl)butyrate and the amounts ofphosphorus compound listed in the tables and extruded several times bymeans of a laboratory extruder (short-compression zone screw, diameterof screw 20 mm; length 400 mm, length of nozzle 30 mm, 2 mm diameter;speed: 125 rpm; temperature program: 200°/230°/230° C.). After the 1st,5th and 10th pass, samples were removed from the granules and used tomeasure the melt flow index according to DIN 53 735 and the yellownessas yellowness index according to ASTM D 1925-70. In addition, thegranules of the 1st pass were used to produce extruded sheets of thedimensions 60×60×1 mm, and the yellowness was measured immediately andafter hot storage (7 days at 100° C.).

The results are listed in Tables 3, 4 and 5.

                  TABLE 1                                                         ______________________________________                                        The effect of phosphorus compounds on the processing stability                of polypropylene. Melt flow index MFI 230/5 after multiple                    granulation. (MFI in g/10 min)                                                                    MFI after                                                                                        10th                                                                          granu-                                 Example                                                                              Phosphorus compound                                                                              1st     5th  lation                                 ______________________________________                                        Comp. A                                                                              none               10      15.3 22.2                                   Comp. B                                                                              0.1 g of tris(2,4-di-t-                                                                          6.4     7.0  10.5                                          butylphenyl) phosphite                                                 Comp. C                                                                              0.1 g of commercial phosphite*.sup.)                                                             5.5     5.7  7.8                                    25     0.1 g of (phosphonite according                                                                  6.15    7.8  11.0                                          to the invention)                                                      26     0.1 g of (phosphonite according                                                                  6.4     6.7  7.16                                          to the invention)                                                      27     0.1 g of (phosphonite according                                                                  6.2     7.3  8.6                                           to the invention)                                                      28     0.1 g of (phosphonite according                                                                  6.1     6.3  11.3                                          to the invention)                                                      29     0.1 g of (phosphonite according                                                                  6.6     8.0  9.4                                           to the invention)                                                      30     0.1 g of (phosphonite according                                                                  5.4     6.0  5.9                                           to the invention)                                                      ______________________________________                                         *.sup.) Tetrakis(2,4di-t-butylphenyl) 4,4biphenylenediphosphonite        

                  TABLE 2                                                         ______________________________________                                        Change in color (yellowness index according to ASTM D                         1925-70) after multiple granulation of polypropylene.                                             MFI [sic] after                                                                                  10th                                                                          granu-                                 Example                                                                              Phosphorus compound                                                                              1st     5th  lation                                 ______________________________________                                        Comp. A                                                                              none               18.7    25.7 27.7                                   Comp. B                                                                              0.1 g of tris(2,4-di-t-                                                                          13.3    23.0 30.4                                          butylphenyl) phosphite                                                 Comp. C                                                                              0.1 g of commercial phosphite*.sup.)                                                             12.8    21.0 26.1                                   25     0.1 g of (phosphonite according                                                                  21.5    34.4 39.5                                          to the invention)                                                      26     0.1 g of (phosphonite according                                                                  8.0     16.4 27.0                                          to the invention)                                                      27     0.1 g of (phosphonite according                                                                  15.8    27.7 36.7                                          to the invention)                                                      28     0.1 g of (phosphonite according                                                                  9.8     18.3 27.3                                          to the invention)                                                      29     0.1 g of (phosphonite according                                                                  20.6    24.0 32.0                                          to the invention)                                                      30     0.1 g of (phosphonite according                                                                  7.4     11.7 16.3                                          to the invention)                                                      ______________________________________                                         *.sup.) Tetrakis(2,4di-t-butylphenyl) 4,4biphenylenediphosphonite        

                  TABLE 3                                                         ______________________________________                                        The effect of phosphorus compounds on the processing stability                of polypropylene. Melt flow index MFI 230/5 after multiple                    granulation. (MFI in g/10 min)                                                                    MFI after                                                                                        10th                                                                          granu-                                 Example                                                                              Phosphorus compound                                                                              1st     5th  lation                                 ______________________________________                                        Comp. D                                                                              none               6.3     8.8  14.9                                   Comp. E                                                                              0.05 g of tris(2,4-di-t-                                                                         5.2     6.4  6.4                                           butylphenyl) phosphite                                                 Comp. F                                                                              0.05 g of commercial phosphite*.sup.)                                                            4.9     5.5  6.4                                    31     0.05 g of (phosphonite according                                                                 4.1     5.7  6.7                                           to the invention)                                                      32     0.05 g of (phosphonite according                                                                 4.3     4.3  4.4                                           to the invention)                                                      33     0.05 g of (phosphonite according                                                                 4.3     4.8  5.2                                           to the invention)                                                      34     0.05 g of (phosphonite according                                                                 4.4     4.4  5.4                                           to the invention)                                                      35     0.05 g of (phosphonite according                                                                 4.4     5.8  7.1                                           to the invention)                                                      36     0.05 g of (phosphonite according                                                                 4.6     4.9  5.6                                           to the invention)                                                      ______________________________________                                         *.sup.) Tetrakis(2,4di-t-butylphenyl) 4,4biphenylenediphosphonite        

                  TABLE 4                                                         ______________________________________                                        Change of color (yellowness index according to ASTM D                         1925-70) after multiple granulation of polypropylene.                                             YI after                                                                                         10th                                                                          granu-                                 Example                                                                              Phosphorus compound                                                                              1st     5th  lation                                 ______________________________________                                        Comp. D                                                                              none               13.7    32.7 35.5                                   Comp. E                                                                              0.05 g of tris(2,4-di-t-                                                                         15.5    27.8 36.1                                          butylphenyl) phosphite                                                 Comp. F                                                                              0.05 g of commercial phosphite*.sup.)                                                            8.7     19.4 26.0                                   31     0.05 g of (phosphonite according                                                                 8.7     23.2 33.4                                          to the invention)                                                      32     0.05 g of (phosphonite according                                                                 9.2     14.9 19.3                                          to the invention)                                                      33     0.05 g of (phosphonite according                                                                 10.0    15.1 21.0                                          to the invention)                                                      34     0.05 g of (phosphonite according                                                                 10.3    16.8 22.4                                          to the invention)                                                      35     0.05 g of (phosphonite according                                                                 14.7    30.2 38.5                                          to the invention)                                                      36     0.05 g of (phosphonite according                                                                 12.5    23.0 30.0                                          to the invention)                                                      ______________________________________                                         *.sup.) Tetrakis(2,4di-t-butylphenyl) 4,4biphenylenediphosphonite        

                  TABLE 5                                                         ______________________________________                                        Change in color on 1 mm extruded sheets immediately                           after production and after heat treatment                                     (7 days at 100° C.)                                                              YI immediately                                                                          YI after 7 days                                           ______________________________________                                        Comp. A     4.2         10.1                                                  Comp. B     3.4         13.0                                                  Comp. C     4.5         12.5                                                  25          6.2         14.9                                                  26          2.7         9.9                                                   27          3.8         13.1                                                  28          2.7         10.8                                                  29          3.3         13.3                                                  30          2.2         10.6                                                  Comp. D     3.5         5.6                                                   Comp. E     4.7         6.6                                                   Comp. F     2.9         3.8                                                   31          2.2         3.2                                                   32          2.4         3.4                                                   33          2.5         3.5                                                   34          2.6         4.0                                                   35          4.1         6.0                                                   36          3.5         4.6                                                   ______________________________________                                         ##STR3##

We claim:
 1. A process for the preparation of aryl phosphonites of theformula (V)in which A is non-existent or a direct bond or a divalenthydrocarbon bridge having 1 to 6 carbon atoms which may be substitutedby groups mentioned further below under R¹, or is a hetero atom,cycloalkylidene having 4 to 8 carbon atoms or phenylalkylidene having 7to 12 carbon atoms, n is 1 or 2, R¹ as monovalent radical is anon-aromatic hydrocarbon radical having 1 to 18 carbon atoms, a phenylor benzyl radical, each of which can carry 1 to 3 substituents, or isα-methylbenzyl, α,α-dimethylbenzyl, naphthyl or a naphthyl radicalcarrying 1 to 5 substituents, in which the substituents are identical ordifferent and are a non-aromatic hydrocarbon radical, an alkoxy radical,an alkylthio radical or a dialkylamino radical, in which the alkylradicals each have 1 to 8 carbon atoms, aryl or aryloxy each having 6 to10 carbon atoms or halogen having an atomic number from 9 to 35, and asdivalent radical a phenylene radical which is unsubstituted or issubstituted by up to 2 non-aromatic hydrocarbon radicals each having 1to 8 carbon atoms or a naphthylene radical which is unsubstituted orcarries 1 to 4 non-aromatic hydrocarbon radicals each having 1 to 8carbon atoms as substituents; or, if both phenyl radicals are bonded viaA, can also be biphenylene, R² is a non-aromatic hydrocarbon radicalhaving 1 to 18 carbon atoms, aryl, arylmethyl, arylethyl orarylisopropyl, in which the aryl in each case contains 6 to 10 carbonatoms, and R³ is hydrogen or a group mentioned under R², which comprisesreacting in a first step a hydrocarbon halide R¹ (-Hal)_(n), in which R¹has the above-mentioned meaning, n is=1 or 2 and the halogen has anatomic weight of at least 35, under Grignard conditions with at leastmolar amounts of magnesium to give the corresponding Grignard compoundsR¹ (MgHal)_(n) and reacting these in a second step with bisarylhalophosphonites of the formula VI ##STR4## in which A, R², R³ and Halhave the above-mentioned meaning, with the formation of the arylphosphonites (V).
 2. The process as claimed in claim 1, wherein Hal inthe substituents of R¹ is chlorine or bromine.
 3. The process as claimedin claim 2, wherein R¹ is naphthyl or a derivative thereof containing analkyl radical of 1 to 4 carbon atoms.
 4. The process as claimed in claim1, wherein R² is a non-aromatic hydrocarbon radical having up to 12carbon atoms.
 5. The process as claimed in claim 4, wherein thenon-aromatic hydrocarbon radical has 4 to 10 carbon atoms.
 6. Theprocess as claimed in claim 1, wherein the reaction temperature in thesecond step is between -30° C. and +30° C.
 7. The process as claimed inclaim 1, wherein the reaction temperature in the second steps is between-20° C. and +20° C.
 8. An aryl phosphonite of the formula (I) ##STR5##in which n is 1 or 2, R¹ as monovalent radical is a naphthyl radicalwhich is unsubstituted or is substituted by 1 to 5 substituents, whichcan be identical or different and are a non-aromatic hydrocarbonradical, an alkoxy radical, an alkylthio radical or a dialkylaminoradical, in which the alkyl radicals each have 1 to 8 carbon atoms, arylor aryloxy each having 6 to 10 carbon atoms or halogen having an atomicnumber from 9 to 35, and as divalent radical a naphthylene radical whichis unsubstituted or carries 1 to 4 non-aromatic hydrocarbon radicalseach having 1 to 8 carbon atoms as substituents or a phenylene radicalwhich is unsubstituted or is substituted by up to 2 non-aromatichydrocarbon radicals each having 1 to 8 carbon atoms,R² is anon-aromatic hydrocarbon radical having 1 to 18 carbon atoms, aryl,arylmethyl, arylethyl or arylisopropyl, in which the aryl in each casecontains 6 to 10 carbon atoms, and R³ is hydrogen or a group mentionedunder R².
 9. The compound as claimed in claim 8, wherein n is 1, and R¹is an unsubstituted or substituted naphthyl radical.
 10. The compound asclaimed in claim 9, wherein R² and R³ each are alkyl radicals having 4to 10 carbon atoms.
 11. A process for the preparation of arylphosphonites of the formula (I) ##STR6## in which n and R¹, R² and R³have the meaning according to following claim 8, which comprisesreacting in a first step a hydrocarbon halide R¹ (-Hal)_(n), in which R¹has the above-mentioned meaning, n is=1 or 2 and the Hal is chlorine orbromine, under Grignard conditions with at least molar amounts ofmagnesium to give the corresponding Grignard compounds R¹ (MgHal)_(n)and reacting these in a second step at temperatures of from -30° C. to+30° C. with bisaryl halophosphonites of the formula (VI) ##STR7## inwhich R², R³ and Hal have the above-mentioned meaning, with theformation of the aryl phosphonites (I).
 12. The process as claimed inclaim 11, wherein the temperature of the second step is from -20° C. to+30° C.
 13. A plastic molding composition containing a thermoplastic orthermoset plastic and an aryl phosphonite of the formula (I) ##STR8## ina ratio of (90 to 99.99):(0.1 to 10), in which in formula (I) n, R¹, R²and R³ have the same meaning as in claim
 8. 14. The plastic moldingcomposition as claimed in claim 13, wherein the plastic is a polyolefin.15. The plastic molding composition as claimed in claim 14, wherein thepolyolefin is polypropylene.
 16. The plastic molding composition asclaimed in claim 13, which containsa) the thermoplastic or thermosetplastic, b) the phosphonite of the formula (I) and c) an ester of c₁) of3,3-bis(3'-t-butyl-4'-hydroxyphenyl)butyric acid of the formula (III)##STR9## in which n is 1 or 2 and R⁴ is a C₁ - to C₁₂ -alkyl radical, ifn is 1, or is a C₁ - to C₁₂ -alkylene radical, if n is 2, or c₂) ofβ-(3,5-t-butyl-4-hydroxyphenyl)propionic acid of the formula (IV)##STR10## with a mono- to tetrahydric alcohol in a ratio of a:b:c of (90to 99.98):(0.01 to 5):(0.01 to 5) % by weight.
 17. A plastic moldingcomposition as claimed in claim 13, which additionally containsadditives from at least one member of the group consisting ofantioxidants, UV absorbers, light stabilizers, metal deactivators,peroxide-destroying compounds, basic co-stabilizers, nucleating agents,fillers, reinforcing agents, plasticizers, lubricants, emulsifiers,pigments, optical brighteners, flame retardants, antistats or blowingagents.